211530421 has 8 divisors (see below), whose sum is σ = 214694424. Its totient is φ = 208373760.

The previous prime is 211530377. The next prime is 211530427. The reversal of 211530421 is 124035112.

It can be written as a sum of positive squares in 4 ways, for example, as 264196 + 211266225 = 514^2 + 14535^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211530421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211530427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87651 + ... + 90031.

It is an arithmetic number, because the mean of its divisors is an integer number (26836803).

Almost surely, 2^211530421 is an apocalyptic number.

It is an amenable number.

211530421 is a deficient number, since it is larger than the sum of its proper divisors (3164003).

211530421 is a wasteful number, since it uses less digits than its factorization.

211530421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3671.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 211530421 is about 14544.0854301671. The cubic root of 211530421 is about 595.8326228864.

Adding to 211530421 its reverse (124035112), we get a palindrome (335565533).

The spelling of 211530421 in words is "two hundred eleven million, five hundred thirty thousand, four hundred twenty-one".